Unique race
Race unique
Uniques -- special beings with no colleagues in their race. One of a kind, most often important to the storyline.
Abilities -- whatever is written into the specific creature. The class is used mechanically, so mass-effect spells don't catch lore-valuable characters in the common net.
They turn up in all sorts of places, from Valhalla to UnderDark. Each is its own thing.
